If you're on the flats its fine. If you're using it in a creek for snook and reds a ten foot might be a bit much. That said I just bought a nine and a half foot Orvis eight weight and love it. And I'm considerting an eleven foot switch for areas where my back cast is restricted, but I wouldn't consider an over head cast with that rig if there was a mangrove within a hundred yards.
Bonefish are a very occasional thing for me, I live about a hundred miles too far north for them, but I throw a lot of the same flies on the flats for reds. I will say this. You're going to be throwing small but heavy flies. In the creeks I use a fast six weight. Out on the flats I used a ten weight which was overkill. Its why I bought the eight. But a six was too light for turning a fly over in the wind. I'd think about an eight rather than a seven. But just call some keys fly shops, World Wide Sports man Islamorada is a place to start. Like wise some of the guides. They can probaly give you the info you need. I will say that a lot of the guides use Redingtons, good enough and won't break the bank. You can do better, but I'd look at them.